rt-thread/bsp/raspberry-pico/libraries/pico-sdk/README.md

Pico SDK

The Pico SDK provides the headers, libraries and build system necessary to write programs for the RP2040 based devices such as the Raspberry Pi Pico in C, C++ or assembly language.

The Pico SDK is designed to provide an API and programming environment that is familiar both to non-embedded C developers and embedded C developers alike. A single program runs on the device at a time and starts with a conventional main() method. Standard C/C++ libraries are supported along with C level libraries/APIs for accessing all of the RP2040's hardware include PIO (Programmable IO)

Additionally the Pico SDK provides higher level libraries for dealing with timers, synchronization, USB (TinyUSB) and multi-core programming along with various utilities.

The Pico SDK can be used to build anything from simple applications, full fledged runtime environments such as MicroPython, to low level software such as RP2040's on chip bootrom itself.

Additional libraries/APIs that are not yet ready for inclusion in the Pico SDK can be found in pico-extras.

Documentation

See Getting Started with the Raspberry Pi Pico for information on how to setup your hardware, IDE/environment and for how to build and debug software for the Raspberry Pi Pico and other RP2040 based devices.

See Pico C/C++ SDK to learn more about programming using the Pico SDK, exploring more advanced features, and complete PDF based API documentation.

See Online Pico SDK API docs for HTML based API documentation.

Example code

See pico-examples for example code you can build.

Quick-start your own project

These instructions are exteremly terse, and Linux based only. For detailed steps, instructions for other platforms, and just in general, we recommend you see Pico C/C++ SDK

1. Install CMake (at least version 3.12), and GCC cross compiler

   sudo apt install cmake gcc-arm-none-eabi libnewlib-arm-none-eabi
   

2. Set up your project to point to use the Pico SDK

   • By cloning the Pico SDK locally (most common)

     1. git clone this Pico SDK repository

     2. Copy pico_sdk_import.cmake from the SDK into your project directory

     3. Set PICO_SDK_PATH to the SDK location in your environment, or pass it (-DPICO_SDK_PATH=) to cmake later.

     4. Setup a CMakeLists.txt like:

        cmake_minimum_required(VERSION 3.12)
        
        # initialize the SDK based on PICO_SDK_PATH
        # note: this must happen before project()
        include(pico_sdk_import.cmake)
        
        project(my_project)
        
        # initialize the Pico SDK
        pico_sdk_init()
        
        # rest of your project
        
        

   • With Pico SDK as a submodule

     1. Clone the SDK as a submodule called pico-sdk

     2. Setup a CMakeLists.txt like:

        cmake_minimum_required(VERSION 3.12)
        
        # initialize pico_sdk from submodule
        # note: this must happen before project()
        include(pico-sdk/pico_sdk_init.cmake)
        
        project(my_project)
        
        # initialize the Pico SDK
        pico_sdk_init()
        
        # rest of your project
        
        

   • With automatic download from github

     1. Copy pico_sdk_import.cmake from the SDK into your project directory

     2. Setup a CMakeLists.txt like:

        cmake_minimum_required(VERSION 3.12)
        
        # initialize pico_sdk from GIT
        # (note this can come from environment, CMake cache etc)
        set(PICO_SDK_FETCH_FROM_GIT on)
        
        # pico_sdk_import.cmake is a single file copied from this SDK
        # note: this must happen before project()
        include(pico_sdk_import.cmake)
        
        project(my_project)
        
        # initialize the Pico SDK
        pico_sdk_init()
        
        # rest of your project
        
        

3. Setup a CMake build directory. For example, if not using an IDE:

   $ mkdir build
   $ cd build
   $ cmake ..
   

4. Write your code (see pico-examples or the Pico C/C++ SDK documentation for more information)

   About the simplest you can do is a single source file (e.g. hello_world.c)

   #include <stdio.h>
   #include "pico/stdlib.h"
   
   int main() {
       setup_default_uart();
       printf("Hello, world!\n");
       return 0;
   }
   

   And add the following to your CMakeLists.txt:

   add_executable(hello_world
       hello_world.c
   )
   
   # Add pico_stdlib library which aggregates commonly used features
   target_link_libraries(hello_world pico_stdlib)
   
   # create map/bin/hex/uf2 file in addition to ELF.
   pico_add_extra_outputs(hello_world)
   

   Note this example uses the default UART for stdout; if you want ot use the default USB see the hello-usb example.

5. Make your target from the build directory you created.

   $ make hello_world
   

6. You now have hello_world.elf to load via a debugger, or hello_world.uf2 that can be installed and run on your Raspberry Pi Pico via drag and drop.